JPH0774494A - Radio wave absorption panel - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a radio wave absorption panel that is lightweight, easy to manufacture, has excellent radio wave absorption characteristics, has a wide band, and can cover the entire TV frequency band. [Structure] The radio wave absorption panel 10 is made of a material obtained by mixing 10 to 50% by weight of ferrite powder with calcium silicate or calcium silicate containing a filler (extending material), and has a plate-like shape with a groove portion 16 formed on the surface. It comprises a molded body 12 and a ferrite tile 14 continuously mounted in the groove. A plurality of groove portions are arranged in parallel at intervals of about 10 to 50% of the groove width, and ferrite tiles are arranged. In order to increase the mechanical strength, the metal mesh 18 is embedded in the plate-shaped molded body. Further, the surface exterior board 22 made of calcium silicate containing ferrite powder may be attached to the surface on which the ferrite tile is mounted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave absorbing panel used as an outer wall material of a high-rise building, and more specifically, it is obtained by applying a ferrite tile to a plate-shaped compact made of calcium silicate containing ferrite powder. The present invention relates to a radio wave absorption panel having a structure that is attached and integrated.

[0002]

2. Description of the Related Art In a super high-rise building, an outer wall material having a radio wave absorbing function is used in order to prevent reflection of TV signals by the building. This is because a ghost appears on the TV screen due to the influence of reflection from a large building. A typical example of the outer wall material is an electromagnetic wave absorption precast concrete curtain wall. This is a structure in which reinforcing bars are arranged inside, lightweight concrete is poured in a plate shape, a ferrite tile is attached to one surface thereof, and the surface is covered with a surface exterior material such as stone or tile.

For example, in the case of a curtain wall of 4 m × 3.2 m square, the concrete thickness of about 15 cm is required, and the weight of 6150 kg per sheet. In the precast concrete curtain wall having such a structure, the absorption of radio waves is performed only by the arranged ferrite tiles.

[0004]

In the conventional electromagnetic wave absorption precast concrete curtain wall used, the reflection loss is 20 at the adaptive frequency of 95 to 110 MHz.
It is about dB. This is extremely insufficient, since there are only 1 to 2 channels of TV frequency.

In addition, since it is very heavy as described above, not only the cost for manufacturing and transportation increases, but also the weight of the entire building increases, and the cost for foundation work and steel frame work increases. .

An object of the present invention is to provide a radio wave absorption panel which is lightweight, easy to manufacture, has an excellent radio wave absorption characteristic, has a wide band, and can cover the entire TV frequency band.

[0007]

The present invention comprises a material in which ferrite powder is mixed in an amount of 10 to 50% by weight with respect to calcium silicate or calcium silicate containing a filler (extending material), and a groove portion is formed on the surface. It is an electromagnetic wave absorption panel comprising a formed plate-shaped body and a ferrite tile continuously mounted in the groove. The direction perpendicular to the longitudinal direction of the groove is
It is preferable that a plurality of groove portions are arranged in parallel at intervals of about 10 to 50% with respect to the width dimension of the groove portions, and ferrite tiles are arranged in these groove portions.

Usually, in order to increase the mechanical strength, a metal mesh is embedded inside the plate-shaped body. A surface exterior board may be attached to the surface on which the ferrite tile is mounted. In that case, the calcium silicate board containing a ferrite powder can be used also for a surface exterior board.

[0009]

FUNCTION Calcium silicate containing 10 to 50% by weight of ferrite powder has a magnetic permeability of about 1 to 10. Then, by mounting the radio wave absorption panel on the outer wall of the building in such a direction that the magnetic field direction of the arriving radio wave coincides with the continuous arrangement direction of the ferrite tiles, the radio wave can be efficiently absorbed. By adjusting the filling amount of the ferrite powder, the radio wave absorption characteristic, that is, the width of the absorption band can be controlled, and the TV radio wave can be adjusted to the frequency band used.

[0010]

1 is an explanatory view showing an embodiment of a radio wave absorption panel according to the present invention, and FIG. 2 is a sectional view thereof. The radio wave absorption panel 10 of the present invention includes a plate-shaped molded body 12 of ferrite-containing calcium silicate and a ferrite tile 14. The plate-shaped compact 12 is made of a material in which 10 to 50% by weight of ferrite powder is mixed with calcium silicate or calcium silicate containing a filler (extending material). The calcium silicate and the filler may be materials commonly used in building materials. The ferrite powder is, for example, magnesium-zinc based sintered powder. The plate-shaped molded body 12 has a plurality of continuous, wide and shallow groove portions 16 formed on one surface thereof at regular intervals. A large number of ferrite tiles 14 are continuously mounted in the groove portions 16. Ferrite tile 14
Is, for example, a magnesium-zinc-based thin plate-shaped sintered body, the thickness of which corresponds to the depth of the groove portion 16, is buried in a flush state, and is attached by an adhesive. Here, the interval L ₂ between the ferrite tile rows is set to approximately 10 to 50% of the ferrite tile width (width of the groove portion) L ₁ . For example, the size of the ferrite tile width L ₁ is 100 mm, and the interval L ₂ between the ferrite tile rows is 45 mm.

A metal mesh 18 is preferably embedded inside the plate-shaped molded body 12 in order to increase the mechanical strength. A resin mold 20 is provided on the side surface of the plate-shaped molded body 12, which is a mold at the time of manufacturing. When a beautiful resin mold is used, it can be attached to the outer wall of a high-rise building without removing it. Plate-shaped molded body 1 equipped with a ferrite tile 14
Surface 2 (the surface where the ferrite tile 14 is attached)
Alternatively, the flat surface exterior board 22 may be attached with a board adhesive. In this surface exterior board 22,
For example, an exterior calcium silicate board containing ferrite powder is suitable. Of course, it is also possible to use exterior tiles or stone plates for other building materials.

As shown in FIG. 1, TV electric waves have a horizontal electric field direction and a vertical magnetic field direction. Therefore, during construction, the direction in which the ferrite tiles 14 are continuously arranged should be the vertical direction. Then, it will be attached to the building. That is, the gap ratio of the ferrite tile in the magnetic field direction is 0%, and the gap ratio of the ferrite tile in the electric field direction is 10 to 50%.

Calcium silicate, which is the main component, is lightweight, and since the radio wave absorption panel has good radio wave absorption performance, it can be made thin, and the weight is reduced as a whole. For example, as a radio wave absorption panel of 4 m × 3.2 m square, the thickness including the surface exterior board can be set to about 8 cm, and the weight per one sheet is about 2560 kg. This is about 40% of the weight of a conventional radio wave absorption precast concrete curtain wall of the same size. In addition, the plate-shaped molded body having the groove portion can be extruded in terms of shape and material, and mass production in a factory is possible. Furthermore, calcium silicate and ferrite powder (oxide) have the advantages that they are stable as building materials and have excellent fire resistance.

FIG. 3 shows the simulation result of the radio wave absorption experiment. The solid line is the characteristic of the product of the present invention. The simulation conditions of the product of the present invention are as follows. Material of plate-shaped body: calcium silicate Mg-Zn ferrite powder (mixed amount: 40% by weight) Permeability of plate-shaped body: μ '= 3, μ "= 0.1 Ferrite tile material: Mg- Zn-based ferrite Ferrite tile thickness: 11 mm Ferrite tile arrangement status Gap ratio in magnetic field direction (vertical direction): 0% (continuous) Gap ratio in electric field direction (horizontal direction): 40%

The product of the present invention is about 5 as shown by the solid line in FIG.
20d over a wide band from 0 to 1000MHz, that is, over a wide TV frequency band including the VHF band and the UHF band
It exhibits a high reflection loss of B or more. By the way, the broken line is the data released by the electromagnetic wave absorption precast concrete curtain wall used by the new Tokyo Metropolitan Government (Shinjuku Ward) in Tokyo. This is about 20 dB at 95 to 110 MHz. It can be seen that the product of the present invention has significantly improved radio wave absorption characteristics as compared with the conventional product.

[0016]

As described above, the present invention is a radio wave absorption panel having a structure in which a ferrite tile is attached to a plate-shaped molded body made of calcium silicate containing ferrite powder, and therefore, the radio wave absorption characteristics are significantly improved. It is possible to improve and increase the bandwidth significantly to cover the entire TV frequency band. In addition, since lightweight calcium silicate is used as the main component and the plate thickness can be reduced to about 1/2 to 1/4 of the conventional thickness, the weight of the panel can be reduced and the construction cost can be reduced. is there.

The radio wave absorption panel according to the present invention has calcium silicate and ferrite as main components, and is excellent in stability and fire resistance as a building material. Further, since the plate-shaped molded body of calcium silicate and ferrite powder can be extruded, it can be mass-produced at the factory and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a radio wave absorption panel according to the present invention.

FIG. 2 is a sectional view thereof.

FIG. 3 is a graph showing an example of radio wave absorption characteristics.

[Explanation of symbols]

 10 Electromagnetic Wave Absorption Panel 12 Plate-shaped Formed Body 14 Ferrite Tile 16 Groove 18 Metal Mesh 20 Resin Form 22 Surface Exterior Board

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Ishikura 5-36-11 Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd.

Claims (4)

[Claims] 1. A plate-shaped molded body made of a material containing 10 to 50% by weight of ferrite powder mixed with calcium silicate and having grooves formed on its surface, and a ferrite tile continuously mounted in the grooves. Radio wave absorption panel. 2. A plate-shaped molded body having a groove portion formed on the surface thereof, which is made of a material in which a ferrite powder is mixed in an amount of 10 to 50% by weight with respect to calcium silicate containing a filler, and a ferrite continuously attached to the groove portion. Radio wave absorption panel consisting of tiles. 3. The radio wave absorption panel according to claim 1, wherein a metal mesh is embedded inside the plate-shaped molded body. 4. The radio wave absorption panel according to claim 1, 2 or 3, wherein the surface on which the ferrite tile is mounted is covered with a surface exterior board made of calcium silicate containing ferrite powder.